Feature - Foreseeing floods

A typical forecast for France. Green represents good weather, yellow is possible rain, darker yellow (at bottom center) is Level 3 Hazardous Weather Alert. Image above  courtesy Meteo France. Image on previous page courtesy Gavin Spence, sxc.hu

During the last decade, flash floods have become one of the most significant natural hazards in Europe.

In September 2002, the Cévennes mountain range in south central France experienced a storm that lasted for 15 hours and caused 600 mm (almost 2 feet) of rain within one day — the normal equivalent of one year’s rain in the Paris area. Unexpected flash floods caused the deaths of more than 20 people, and economic damage estimated at 1.2 billion euros (about $1,555,261,897 in US dollars as of press time).

The ability to predict such situations is vital.

“There were not forecasting systems set up at that point (of the 2002 flood),” says Vincent Thierion, a geo-informatics researcher working on a grid-enabled flood forecasting application. “Such events had been rare, and now they are more common, occurring also in 2005, non-catastrophically, last fall in 2008. You have no chance of knowing that one could happen until about one day before.”

To help alleviate the problem, Thierion works on the European project CYCLOPS — Cyber-Infrastructure for CiviL protection Operative ProcedureS — which aims to bridge the gap between European civil protection agencies and the grid technology community. Supporting the work of the French Grand Delta flood forecasting service, CYCLOPS has developed a platform for running the forecasting application, G-ALTHAIR, on a distributed computing grid, and ported this to the Enabling Grids for E-sciencE infrastructure.

This style of computing allows the application to multi-task: researchers can run forecasts for several watersheds, and for several rainfall scenarios at once, incorporating new data or adding additional layers of forecasting complexity in real-time. CYCLOPS researchers hope this will aid authorities in making decisions when managing crises.

Vincent Thierion demonstrates G-ALTHAIR flood-prediction capabilities. Image courtesy GridCast

Advance warnings save property and lives

Currently in prototype phase, G-ALTHAIR  will be in production by 2010, Thierion believes.

Using data from 170 regional monitoring stations spread around France’s flood-prone zone, and radar images and rainfall forecasts from Meteo France weather service, the application gathers local data from regional computer clusters, which simulate the real-time hydrological situation, and forecasts possible scenarios using the grid.

“The existing system is mostly dedicated to monitoring a flash flood which is already occurring,” Thierion says. “The innovation I think is important is to use the abilities of the grid to the prevent damage. With it we can share richer hydrological information with the civil protection services, to protect the population.”

Thierion demonstrated G-ALTHAIR at the 4th Enabling Grids for E-sciencE User Forum in Italy in early March, watch his demonstration through the GridCast video blog.

—Danielle Venton, EGEE